Typical input mechanisms for electronic devices and computers include button mechanisms and mechanical actuation switches. These input mechanisms can be subject to failure through repeated use. They require multiple components that can move relative to one another, and may require hinges, springs or joints that are subject to fatigue.
Another type of input mechanism is a digitizer. The digitizer can detect contact on a surface that is typically incorporated with a display. The digitizer may be a component of small computing devices, such as handheld computers, or personal digital assistants (PDAs). An assembly of the digitizer assigns identifying voltage values for different contact points distributed across the digitizer's surface. This allows the user to distinguish a communication by positioning an external object on a specific position of the digitizer.
Inputs such as gestures, taps, and drags are made on the surface of the digitizer through contact. Icons or other visual cues may be employed with the digitizer to give a user an indication that contact with a specific position on the digitizer will cause a processor of the device to perform a specific function. Digitizers are relatively planar, so that contact points on the surface of the digitizer are positions on the same plane. When users enter input through a digitizer, the user selects planar positions on the digitizer's surface for contact with the external object.
FIG. 10 is an illustration of a prior art display module 900. The display module 900 is contact-sensitive to produce electrical signals in response to contact. The electrical signals are subsequently converted to input. The display module 900 includes an exterior layer 910, a conductive layer 920, a substrate 930 and a display 940. The exterior layer 910 is a polyester (PET) film. The conductive layer 920 comprises a first conductive film 922, an air gap 926 formed by spacers 945, and a second conductive film 924. The conductive films 922, 924 are formed of Indium Tin Oxide material, which has a paste constituency. The spacers 945 are formed from glass or plastic. The substrate 930 is also formed from glass or plastic. The layers formed above display 940 provide a digitizer for the device. The combination of layers for the digitizer is clear to enable viewing of an image created by display 940.
Mechanical buttons are sometimes preferred for certain functions because they provide a better tactile feedback for the function being requested by the input. For example, navigation buttons for scrolling a display of a handheld computer are often mechanical buttons, because they provide a better feel of movement being created when scrolling the display.